This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 20 |
| 5 | 89 |
| 6 | 569 |
| 7 | 4002 |
| 8 | 31899 |
| 9 | 266736 |
| 10 | 2315811 |
| 11 | 20531349 |
| 12 | 184927106 |
| 13 | 1684835315 |